289Kh/s out a 280x dunno if this is any thing new but it was to me LOL
for details https://i.imgur.com/bKGSMYq.png
You are lucky)for details https://i.imgur.com/bKGSMYq.png
I have 99% hw on my giga 280x, if set i 13. I try it with any parameters... Normal work only with i 12...